Two-component polyurethane photovoltaic sealing water-blocking glue and preparation method thereof
The porous hybrid microspheres prepared by the sol-gel method react with NCO-terminated polyurethane prepolymer to form a dense cross-linked network, which solves the problem of poor water barrier performance of photovoltaic module encapsulation materials, improves water vapor barrier performance and aging resistance, and prevents the occurrence of PID effect.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- COLLTECH DONGGUAN BONDING TECH CO LTD
- Filing Date
- 2026-03-23
- Publication Date
- 2026-05-12
AI Technical Summary
The poor water-blocking performance of existing photovoltaic module encapsulation materials leads to the formation of leakage current channels, which in turn induces the PID effect, resulting in rapid degradation of module performance.
Porous hybrid microspheres prepared by the sol-gel method were used as raw materials for water-blocking adhesives. The porous hybrid microspheres prepared by organosilicon compounds, nano-silica and polyvinyl alcohol are rich in silanol and alcohol hydroxyl groups on the surface. They form a dense cross-linked water-blocking network by reacting with NCO-terminated polyurethane prepolymer.
It improves the water vapor barrier performance of photovoltaic modules, enhances the aging resistance of colloids, avoids structural damage caused by stress concentration, prevents the occurrence of PID effect, and extends the service life of modules.
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Abstract
Description
Technical Field
[0001] This invention belongs to the field of polyurethane adhesive technology, specifically relating to a two-component polyurethane photovoltaic sealing water-blocking adhesive and its preparation method. Background Technology
[0002] Solar energy, as the most common and widely used long-term clean energy source, can be used for both solar thermal power generation (solar thermal effect) and photovoltaic power generation (photovoltaic effect). After more than a decade of development, the photovoltaic industry has become a significant driving force for my country's energy transformation. As the scale of photovoltaic power plants continues to expand, the number of modules connected in series also increases. This leads to a corresponding increase in the voltage across the circuitry and grounded frame of the modules. Under prolonged high voltage, the performance of photovoltaic modules will continuously decline, a phenomenon known as potential-induced degradation (PID). PID effects are prevalent in photovoltaic power plants. However, most power plants address PID by replacing modules after their power output has decreased to a certain level. This method not only increases costs unnecessarily but also affects the power generation efficiency and economic benefits of the photovoltaic power plant. Preventing PID effects in photovoltaic modules from the source and avoiding performance degradation has become a crucial technical challenge for the photovoltaic industry. Research shows that the generation of PID effects in photovoltaic modules is closely related to leakage current, and the generation and conduction of leakage current are closely related to water vapor penetration and interface sealing performance at the module encapsulation points. In the actual operation of photovoltaic power plants, changes in temperature and humidity in the environment can cause leakage current to form between the solar cells and the grounding frame. The connection between the photovoltaic module's encapsulation material, backsheet, glass and frame is prone to leakage current channels due to poor sealing and water resistance. Moisture penetration will further reduce the interface insulation performance, accelerate the conduction of leakage current, and thus induce and aggravate the PID effect, leading to rapid degradation of module performance.
[0003] Photovoltaic water-blocking adhesive is a core material in the photovoltaic module encapsulation process. It is mainly used for sealing the module frame, backsheet and glass. Its water-blocking performance, insulation performance, adhesion performance and environmental aging resistance directly determine the sealing reliability of the module interface, and thus affect the formation of leakage current channels and the probability of PID effect. Therefore, starting from the source of materials, developing high-performance water-blocking adhesives that combine ultra-low water vapor transmission rate, strong adhesion to multiple substrates, and resistance to aging in complex environments is one of the main methods to prevent the PID effect of modules and block the initial performance degradation from the source. Researchers in this field have done a lot of work on developing high-performance water-blocking adhesives with low water vapor transmission rate, strong adhesion to multiple substrates, and resistance to aging in complex environments. For example, patent CN106811153B discloses a water-blocking adhesive for sealing photovoltaic modules. This adhesive is mainly composed of olefin polymers, silane-modified olefin polymers, superabsorbent resins, reinforcing fillers, inert fillers, desiccants, and antioxidants mixed in a mass ratio of 100:5-30:2-10:10-20:20-40:5-10:0.1-0.5. This patent introduces a highly absorbent resin that can absorb water to form a gel-like substance, effectively locking in moisture and forming a gel barrier to improve water vapor barrier properties. However, there is a secondary risk of absorbing water first and then releasing it at high temperatures. Furthermore, the gel-like substance will swell after absorbing water, and the volume expansion will damage the interface between the colloid and the frame / glass, exacerbating water vapor transmission. Patent CN119242247A discloses a polyurethane water-blocking adhesive for photovoltaic module frames and its preparation method, comprising component A and component B in a volume ratio of (0.8-1.2):1; component A includes: 5-10 parts by weight of modified castor oil polyol; 10-20 parts by weight of polyester polyol; 5-20 parts by weight of liquid polybutadiene polyol; 1-3 parts by weight of chain extender; 5-15 parts by weight of plasticizer; 20-40 parts by weight of asphalt; 20-40 parts by weight of filler; 1-3 parts by weight of silica; and 0.2-2 parts by weight of tackifier; component B includes: 15-40 parts by weight of isocyanate; 10-40 parts by weight of liquid polybutadiene polyol; 10-20 parts by weight of plasticizer; 10-30 parts by weight of asphalt; 20-40 parts by weight of filler; 1-3 parts by weight of silica; 0.2-2 parts by weight of antioxidant; and 0.2-2 parts by weight of water absorbent. This patent uses a large amount of asphalt and multifunctional polyols to improve hydrophobicity and crosslinking degree to prevent creep, reduce water vapor permeability, and improve water blocking effect. However, asphalt contains a large number of unsaturated bonds and small molecule volatiles. Asphalt softens and flows at high temperatures, contaminating the glass surface of the component and causing a loss of power generation efficiency. Small molecule volatiles migrate under high temperature or humid conditions, destroying the colloidal interface bonding state, resulting in a significant decrease in tensile shear strength, adhesion failure, and reduced sealing reliability.
[0004] Therefore, it is necessary to develop a water-blocking adhesive that combines excellent water-blocking performance, mechanical properties, and environmental aging resistance to overcome the shortcomings of existing water-blocking adhesives, prevent the occurrence of PID effect in photovoltaic modules from the source, and avoid module performance degradation. Summary of the Invention
[0005] To address the aforementioned technical problems, this invention provides a two-component polyurethane photovoltaic sealing water-blocking adhesive and its preparation method. The water-blocking adhesive raw material of this invention includes a porous hybrid microsphere prepared by a sol-gel method using an organosilicon compound as a precursor, nano-silica as a reinforcing component, and polyvinyl alcohol as an organic component. Its surface is rich in silanol and alcohol hydroxyl groups and has a porous structure, which can adsorb water vapor, giving the water-blocking adhesive excellent water vapor barrier function. At the same time, the silanol and alcohol hydroxyl groups on the surface of the microsphere can react with the NCO groups on the NCO-terminated polyurethane prepolymer to form chemical crosslinks, forming a dense crosslinked water-blocking network inside the colloid, further improving the water vapor barrier performance.
[0006] To achieve the above objectives, the following technical solution is adopted:
[0007] A two-component polyurethane water-blocking adhesive for photovoltaic sealing, comprising two components, A and B, in a mass ratio of 0.8-1:1.
[0008] Component A comprises the following raw materials in parts by weight: 30-40 parts of a first polyol, 5-8 parts of porous hybrid microspheres, 10-20 parts of filler, 30-40 parts of a first flame retardant, and 0.1-0.3 parts of a first catalyst; the porous hybrid microspheres are porous organic-inorganic hybrid aerogel materials prepared by the sol-gel method using an organosilicon compound as a precursor, nano-silica as a reinforcing component, and polyvinyl alcohol as an organic component; the mass ratio of the organosilicon compound, nano-silica, and polyvinyl alcohol is 3-5:0.1-0.5:1;
[0009] The B component comprises the following raw materials in parts by weight: 40-50 parts of NCO-terminated polyurethane prepolymer, 10-20 parts of filler, and 30-40 parts of a second flame retardant; the NCO-terminated polyurethane prepolymer is prepared by reacting a second polyol with a diisocyanate; the -NCO content of the NCO-terminated polyurethane prepolymer is 8-12 wt%.
[0010] Furthermore, the mass ratio of the organosilicon compound, nano-silica, and polyvinyl alcohol is 3-5:0.1-0.3:1.
[0011] The average particle size of the nano-silica is 15-60 nm.
[0012] Doping porous hybrid microspheres with an appropriate amount of nano-silica can enhance the PCT aging resistance of water-blocking adhesives (PCT aging test is a test that accelerates the hygrothermal aging of materials under high temperature, high pressure, and saturated steam environment to evaluate their resistance to hygrothermal stress, hydrolysis, permeation, and structural stability). It is speculated that an appropriate amount of nano-silica helps form a rigid hybrid framework inside the porous hybrid microspheres, enhancing the structural stability of the microspheres, resisting the thermal shrinkage and creep generated during PCT aging, and preventing structural damage, pore collapse, or interface cracking of the porous hybrid microspheres due to stress concentration. This maintains the overall density and water-blocking reliability of the colloid, preventing the occurrence of PID effect in photovoltaic modules from the source and avoiding module performance degradation. However, it is important to note that the amount and particle size of nano-silica must be strictly controlled. Too much will increase the brittleness of the porous hybrid microspheres and reduce their shear resistance; too little will be insufficient to resist the stress generated during PCT aging.
[0013] The organosilicon compound is selected from one or more combinations of methyl orthosilicate, ethyl orthosilicate, propyl orthosilicate, butyl orthosilicate, methyltrimethoxysilane, and methyltriethoxysilane.
[0014] The weight-average molecular weight of the polyvinyl alcohol is 150,000 to 200,000.
[0015] The average particle size of the porous hybrid microspheres is 1-5 μm.
[0016] Specifically, the preparation method of the porous hybrid microspheres includes the following steps: preparing silica sol using organosilicon compounds as raw materials; mixing the silica sol with nano-silica and polyvinyl alcohol aqueous solution, reacting, freeze-drying, and air-jet milling to obtain porous hybrid microspheres;
[0017] The mixing conditions are as follows: ultrasonication at a power of 100-300W and a frequency of 20-50kHz, with simultaneous stirring at a speed of 150-500rpm for 15-40 minutes. The reaction is carried out at 40-60℃ with stirring at a speed of 100-300rpm for 1-2 hours. The concentration of the polyvinyl alcohol aqueous solution is 8-15wt%. The freeze-drying conditions are as follows: pre-freezing at -30℃ to -55℃ for 1-2 hours, followed by freeze-drying at -45℃ to 40℃, with a pressure of 2-50Pa and a freeze-drying time of 6-48 hours. The air jet milling is performed to pulverize to an average particle size of 1-5μm.
[0018] The method for preparing the silica sol includes the following steps: mixing an organosilicon compound, an organic alcohol, and water, adjusting the pH to 2-4, and reacting at a controlled temperature to obtain the silica sol.
[0019] Further, the mass ratio of the organosilicon compound:organic alcohol:water is 1:1-5:0.1-0.5. The temperature-controlled reaction is carried out at a temperature of 40-60℃ and with stirring at 100-300 rpm for 1-2 hours. The pH is adjusted to 2-4 using 30-37wt% hydrochloric acid. The organic alcohol is selected from one or more combinations of methanol, ethanol, isopropanol, ethylene glycol, propylene glycol, n-butanol, isobutanol, n-pentanol, and isoamyl alcohol.
[0020] The first polyol has a functionality of 2.5-3 and a hydroxyl value of 100-400 mg KOH / g. The first polyol is selected from one or more of modified castor oil polyol, modified palm oil polyol, modified cashew nut shell oil polyol, modified rapeseed oil polyol, and modified soybean oil polyol. Preferably, the first polyol is a modified castor oil polyol with a functionality of 2.6-2.9 and a hydroxyl value of 109-342 mg KOH / g.
[0021] The second polyol has a functionality of 2-3 and a number-average molecular weight of 2000-6000. The second polyol is selected from one or more combinations of hydrogenated hydroxyl-terminated polybutadiene, hydroxyl-terminated polybutadiene, polyethylene glycol, polypropylene glycol, and polypropylene triol. The diisocyanate is selected from one or more combinations of isophorone diisocyanate, toluene diisocyanate, and diphenylmethane-4,4'-diisocyanate. Preferably, the second polyol is hydrogenated hydroxyl-terminated polybutadiene and / or hydroxyl-terminated polybutadiene with a functionality of 2-2.3 and a number-average molecular weight of 3000-5000.
[0022] Specifically, the preparation method of the NCO-terminated polyurethane prepolymer includes the following steps: adding a second polyol to a reaction vessel, dehydrating, cooling for the first time, adding diisocyanate and a second catalyst and mixing, reacting under controlled temperature under vacuum, and cooling for the second time to obtain the NCO-terminated polyurethane prepolymer.
[0023] The dehydration temperature is 115-125℃, and the time is 1-3 hours. The first cooling is to 60-100℃. The vacuum condition is 0.05MPa to 0.09MPa. The temperature-controlled reaction is carried out at 60-80℃ for 3-6 hours. Before the second cooling, the -NCO content is measured to be 8-12%. The cooling is to 20-30℃. The amount of the second catalyst is 0.05-0.2wt% of the total mass of the second polyol and diisocyanate.
[0024] The first catalyst and the second catalyst are independently selected from one or more combinations of organotin catalysts, organobismuth catalysts, and organozinc catalysts. The organotin catalyst is selected from one or more combinations of dibutyltin dilaurate, stannous octanoate, di(dodecyl sulfide)dibutyltin, dibutyltin diacetate, dibutyltin dibutyrate, and dibutyltin dioleate. The organobismuth catalyst is selected from one or more combinations of bismuth neodecanoate, bismuth laurate, bismuth isooctanoate, and bismuth naphthenate. The organozinc catalyst is selected from one or more combinations of zinc isooctanoate, zinc neodecanoate, and zinc naphthenate.
[0025] The fillers in components A and B are selected from one or more of calcium carbonate, glass powder, and silica powder; the average particle size of the fillers is 1-8 μm.
[0026] The first flame retardant and the second flame retardant are independently selected from one or more combinations of aluminum hydroxide, magnesium hydroxide, triphenyl phosphate, resorcinol bis(diphenyl phosphate), bisphenol A-bis(diphenyl phosphate), oligoaryl phosphate, melamine cyanurate, ammonium polyphosphate, melamine phosphate, melamine pyrophosphate, and melamine polyphosphate.
[0027] Furthermore, the first flame retardant and the second flame retardant are independently a mixture of aluminum hydroxide and melamine cyanurate in a mass ratio of 25-35:5-10.
[0028] Component A further includes 1-5 parts by weight of an additive, which is selected from one or a combination of two of antioxidants, light stabilizers, and adhesive accelerators.
[0029] There are no particular limitations on the antioxidants used; any commonly used antioxidants in the field are acceptable. They can be one or a combination of two or more of Irgastab PUR68, antioxidant 1010, and Irganox 5057.
[0030] The light stabilizer is selected from one or a combination of two of benzotriazole light stabilizers and hindered amine light stabilizers; the benzotriazole light stabilizers include, but are not limited to, one or a combination of two of Tinuvin 213 and UV-320; the hindered amine light stabilizers include, but are not limited to, one or a combination of two of (2,2,6,6-tetramethylpiperidine) sebacate and 4-benzoyloxy-2,2,6,6-tetramethylpiperidine.
[0031] The adhesive promoter is selected from one or a combination of two or more of epoxy silane coupling agents, amino silane coupling agents, mercaptosilane coupling agents, and hydroxy silane coupling agents.
[0032] This invention also provides a method for preparing a two-component polyurethane photovoltaic water-blocking adhesive, comprising the following steps:
[0033] 1) Mix the first polyol, porous hybrid microspheres, filler, first flame retardant, and second catalyst, and dehydrate to obtain component A;
[0034] 2) Mix the filler and the second flame retardant, dehydrate, add NCO-terminated polyurethane prepolymer, mix, degas, and obtain component B.
[0035] In step 1), the dehydration is achieved by heating to 115-125℃ and maintaining the temperature for 1-3 hours. The mixing is achieved by stirring at 400-800 rpm for 15-60 minutes.
[0036] In step 2), the dehydration is achieved by heating to 115-125℃ and maintaining the temperature for 1-3 hours. The mixing is achieved by stirring at 400-800 rpm for 30-60 minutes. The degassing is achieved by stirring at 50-150 rpm for 30-60 minutes under a vacuum of 0.05-0.095 MPa.
[0037] Compared with the prior art, the beneficial effects of the present invention are:
[0038] The water-blocking adhesive raw material of this invention includes a porous hybrid microsphere prepared by the sol-gel method using an organosilicon compound as a precursor, nano-silica as a reinforcing component, and polyvinyl alcohol as an organic component. Its surface is rich in silanol and alcohol hydroxyl groups and has a porous structure, which can adsorb water vapor, giving the water-blocking adhesive excellent water vapor barrier function. At the same time, the silanol and alcohol hydroxyl groups on the surface of the microsphere can react with the NCO groups on the NCO-terminated polyurethane prepolymer to form chemical crosslinks, forming a dense crosslinked water-blocking network inside the colloid, further improving the water vapor barrier performance.
[0039] The inventors discovered that doping a suitable amount of nano-silica into porous hybrid microsphere raw materials can enhance the PCT aging resistance of water-blocking adhesives. They speculate that the appropriate amount of nano-silica helps to form a rigid hybrid framework inside the porous hybrid microspheres, enhancing the structural stability of the microspheres, resisting the thermal shrinkage and creep generated during PCT aging, avoiding structural damage, pore collapse, or interface cracking of the porous hybrid microspheres due to stress concentration, maintaining the overall density and water-blocking reliability of the colloid, preventing the occurrence of PID effect in photovoltaic modules from the source, and avoiding module performance degradation. Detailed Implementation
[0040] The present invention will be further described below with reference to specific embodiments, but is not limited to the contents of the specification. Unless otherwise specified, all "parts" mentioned in the embodiments of the present invention are parts by weight. All reagents used are commercially available in the art.
[0041] Nano-silica #1, with an average particle size of 15nm, is from Zhongke Jinyan (Beijing) Technology Co., Ltd.
[0042] Nano-silica #2, with an average particle size of 30nm, is from Zhongke Jinyan (Beijing) Technology Co., Ltd.
[0043] Nano-silica #3, with an average particle size of 60nm, is from Zhongke Jinyan (Beijing) Technology Co., Ltd.
[0044] Polyvinyl alcohol P816864, with a weight-average molecular weight of 195,000, is from Maclean's.
[0045] Polyvinyl alcohol P434368, with a weight-average molecular weight of 146,000, is from Aladdin.
[0046] Hydrogenated hydroxyl-terminated polybutadiene GI3000, functionality 2, number-average molecular weight 3100, is from Japan Soda.
[0047] Hydroxyl-terminated polybutadiene E081624, functionality 2, number average molecular weight 4600, from Energie.
[0048] Modified castor oil polyol Vantrus Polycin® GR110, with a functionality of 2.6 and a hydroxyl value of 109 mg KOH / g, is from Haoyi New Materials.
[0049] Modified castor oil polyol Vantrus Polycin® GR340, with a functionality of 2.9 and a hydroxyl value of 342 mg KOH / g, is from Haoyi New Materials.
[0050] Calcium carbonate, with an average particle size of 5μm, is from Zhejiang Zhijin New Materials Technology Co., Ltd.
[0051] Aluminum hydroxide H-WF-2N, with a median particle size of 1.4 μm, is sourced from Zibo Dongyusheng Chemical Co., Ltd.
[0052] Melamine cyanurate, from Shenzhen Tianruida New Materials Co., Ltd.
[0053] -NCO content was determined according to the di-n-butylamine-hydrochloric acid back titration method in standard GB / T 12009.4-2016.
[0054] Example 1
[0055] 1) Tetraethyl orthosilicate, ethanol, and water were mixed in a mass ratio of 1:5:0.5. The pH was adjusted to 2 with 37wt% hydrochloric acid, and the temperature was controlled at 60℃. The mixture was stirred at 300rpm for 1 hour to obtain silica sol. Polyvinyl alcohol P816864 was dissolved in water at 80℃ to prepare a 10wt% polyvinyl alcohol aqueous solution.
[0056] 2) Silica sol was mixed with nano-silica 1# and a 10wt% polyvinyl alcohol aqueous solution at a mass ratio of tetraethyl orthosilicate, nano-silica 1# and polyvinyl alcohol of 5:0.3:1. The mixing conditions were as follows: ultrasonication at 300W power and 20kHz frequency, stirring at 300rpm for 15min, reaction at 60℃ and stirring at 300rpm for 2h, then pre-frozen at -30℃ for 1h, freeze-dried at -20℃ and 10Pa for 24h, and finally air-jet pulverized to an average particle size of 2.4μm to prepare porous hybrid microspheres.
[0057] 3) Add 1 kg of hydrogenated hydroxyl-terminated polybutadiene GI3000 to the reactor, dehydrate at 125℃ for 1 h, cool down to 60℃, add 0.6 kg of isophorone diisocyanate, and mix with the mass of hydrogenated hydroxyl-terminated polybutadiene GI3000 and isophorone diisocyanate and 0.05 wt% dibutyltin dilaurate. React at 80℃ for 6 h under vacuum of 0.09 MPa. When the -NCO content is measured to be 12 wt%, cool down to 25℃ to obtain NCO-terminated polyurethane prepolymer.
[0058] 4) Mix 40 kg of modified castor oil polyol Polycin® GR110, 8 kg of porous hybrid microspheres, 20 kg of calcium carbonate, 40 kg of a mixed flame retardant consisting of aluminum hydroxide H-WF-2N and melamine cyanurate in a mass ratio of 35:5, 0.1 kg of dibutyltin dilaurate, 0.5 kg of antioxidant 1010, 0.5 kg of UV-320, and 0.5 kg of (3-aminopropyl)trimethoxysilane at 500 rpm for 60 min, heat to 115 °C, and dehydrate for 1.5 h to obtain component A;
[0059] 5) Mix 20 kg of calcium carbonate and 40 kg of a mixed flame retardant consisting of aluminum hydroxide H-WF-2N and melamine cyanurate in a mass ratio of 35:5 at 800 rpm for 15 min. Heat the mixture to 115℃ and dehydrate for 1.5 h. Add 50 kg of NCO-terminated polyurethane prepolymer and mix at 800 rpm for 30 min. Stir and degas at 150 rpm under a vacuum of 0.08 MPa for 30 min to obtain component B.
[0060] 6) Mix components A and B at a mass ratio of 1:1 for sealing the frame during the photovoltaic module encapsulation process.
[0061] Example 2
[0062] The rest is the same as in Example 1, except that in step 2), the mass ratio of tetraethyl orthosilicate, nano silica 1#, and polyvinyl alcohol is 5:0.1:1.
[0063] Example 3
[0064] The rest is the same as in Example 1, except that in step 2), the mass ratio of tetraethyl orthosilicate, nano silica 1#, and polyvinyl alcohol is 3:0.3:1.
[0065] Example 4
[0066] The rest is the same as in Example 1, except that in step 2), nano-silica 2# of equal mass is used to replace nano-silica 1#.
[0067] Example 5
[0068] The rest is the same as in Example 1, except that in step 2), nano-silica 3# of equal mass is used to replace nano-silica 1#.
[0069] Example 6
[0070] The rest is the same as in Example 1, except that in step 4), the amount of porous hybrid microspheres used is 5 kg.
[0071] Example 7
[0072] The rest is the same as in Example 1, except that in step 3), hydrogenated hydroxyl-terminated polybutadiene GI3000 is replaced with an equal mass of hydroxyl-terminated polybutadiene E081624, and the amount of isophorone diisocyanate is 0.55 kg. When the -NCO content is measured to be 12 wt%, the temperature is lowered to 25 °C to obtain NCO-terminated polyurethane prepolymer.
[0073] Example 8
[0074] The rest is the same as in Example 1, except that in step 4), the modified castor oil polyol Polycin® GR110 is replaced with an equal mass of modified castor oil polyol Polycin® GR340.
[0075] Example 9
[0076] The rest is the same as in Example 1, except that in step 3), the amount of hydrogenated hydroxyl-terminated polybutadiene GI3000 is 1 kg and the amount of isophorone diisocyanate is 0.36 kg. When the -NCO content is measured to be 8 wt%, the temperature is lowered to 25°C to obtain NCO-terminated polyurethane prepolymer.
[0077] Example 10
[0078] 1) Methyl orthosilicate, ethanol, and water were mixed in a mass ratio of 1:1:0.1. The pH was adjusted to 2 with 37wt% hydrochloric acid, and the temperature was controlled at 60℃. The mixture was stirred at 300rpm for 1 hour to obtain silica sol. Polyvinyl alcohol P434368 was dissolved in water at 80℃ to prepare a 10wt% polyvinyl alcohol aqueous solution.
[0079] 2) Silica sol was mixed with nano-silica 1# and a 10wt% polyvinyl alcohol aqueous solution at a mass ratio of methyl orthosilicate, nano-silica 1# and polyvinyl alcohol of 5:0.3:1. The mixing conditions were as follows: ultrasonication at 300W power and 20kHz frequency, stirring at 300rpm for 15min, reaction at 60℃ and stirring at 300rpm for 2h, then pre-frozen at -30℃ for 1h, freeze-dried at -20℃ and 10Pa for 24h, and finally air-jet pulverized to an average particle size of 4.6μm to prepare porous hybrid microspheres.
[0080] 3) Add 1 kg of hydroxyl-terminated polybutadiene E081624 to the reactor, dehydrate at 125℃ for 1 h, cool to 60℃, add 0.64 kg of diphenylmethane-4,4'-diisocyanate, and mix with the mass of hydroxyl-terminated polybutadiene E081624 and diphenylmethane-4,4'-diisocyanate and 0.05 wt% dibutyltin dilaurate. React at 80℃ for 6 h under vacuum of 0.09 MPa. When the -NCO content is measured to be 12 wt%, cool to 25℃ to obtain NCO-terminated polyurethane prepolymer.
[0081] 4) Mix 40 kg of modified castor oil polyol Vantrus Polycin® GR340, 8 kg of porous hybrid microspheres, 10 kg of calcium carbonate, 30 kg of a mixed flame retardant consisting of aluminum hydroxide H-WF-2N and melamine cyanurate in a mass ratio of 25:10, 0.1 kg of dibutyltin dilaurate, 0.5 kg of antioxidant 1010, 0.5 kg of UV-320, and 0.5 kg of (3-aminopropyl)trimethoxysilane at 500 rpm for 60 min, heat to 115 °C, and dehydrate for 1.5 h to obtain component A;
[0082] 5) Mix 10 kg of calcium carbonate and 30 kg of a mixed flame retardant consisting of aluminum hydroxide H-WF-2N and melamine cyanurate in a mass ratio of 35:5 at 800 rpm for 15 min. Heat the mixture to 115℃ and dehydrate for 1.5 h. Add 40 kg of NCO-terminated polyurethane prepolymer and mix at 800 rpm for 30 min. Stir and degas at 150 rpm under a vacuum of 0.08 MPa for 30 min to obtain component B.
[0083] 6) Mix components A and B at a mass ratio of 0.8:1 for sealing the frame during the photovoltaic module encapsulation process.
[0084] Comparative Example 1
[0085] The rest is the same as in Example 1, except that in step 2), nano-silica 1# is replaced with an equal mass of nano-calcium carbonate LF-CaCO3-N20 (Ningbo Luofei Nanotechnology Co., Ltd.) with an average particle size of 20nm.
[0086] Comparative Example 2
[0087] The rest is the same as in Example 1, except that in step 2), an aqueous solution of polyvinyl alcohol is not added.
[0088] The water-blocking adhesives prepared in the above examples and comparative examples were subjected to the following performance tests:
[0089] Shear strength: Tested according to standard GB / T 7124-2008 Determination of tensile shear strength of adhesives (rigid material to rigid material), aluminum substrate, rigid material to rigid material.
[0090] PCT aging: The test was conducted in accordance with the standard IEC 60068-2-66, with test conditions of 120℃ / 100%RH / 0.2MPa and a test duration of 240h. The shear strength was retested, and the shear strength loss rate was calculated.
[0091] Water vapor transmission rate: Refer to standard GB / T 26253-2010 Determination of water vapor transmission rate of plastic films and sheets, infrared detector method.
[0092] Table 1 Performance Test Results
[0093]
[0094] As shown in Table 1, the water-blocking adhesive of this invention exhibits excellent water vapor barrier properties, mechanical properties, and aging resistance, with a water vapor transmission rate reaching 0.7-2.4 g / m³. 2 • After 24 hours, the shear strength loss rate is controlled at 0.9-3.4%, and the shear strength can reach 2.8-4.0 MPa.
[0095] The performance test results of Examples 1 and 8 show that when using modified castor oil polyol with a high hydroxyl value, the water-blocking adhesive has a larger shear strength loss rate and lower shear strength. The possible reason is that the modified castor oil polyol can react with the isocyanate on the NCO-terminated polyurethane prepolymer more quickly and easily than the porous hybrid microspheres, and the water-blocking network formed in the water-blocking adhesive is not dense.
[0096] The above detailed description is a specific description of one of the feasible embodiments of the present invention. This embodiment is not intended to limit the patent scope of the present invention. All equivalent implementations or modifications that do not depart from the present invention should be included within the scope of the technical solution of the present invention.
Claims
1. A two-component polyurethane photovoltaic sealing water-blocking adhesive, characterized in that, It includes two components, A and B, with a mass ratio of 0.8-1:
1. Component A comprises the following raw materials in parts by weight: 30-40 parts of a first polyol, 5-8 parts of porous hybrid microspheres, 10-20 parts of filler, 30-40 parts of a first flame retardant, and 0.1-0.3 parts of a first catalyst; the porous hybrid microspheres are porous organic-inorganic hybrid aerogel materials prepared by the sol-gel method using an organosilicon compound as a precursor, nano-silica as a reinforcing component, and polyvinyl alcohol as an organic component; the mass ratio of the organosilicon compound, nano-silica, and polyvinyl alcohol is 3-5:0.1-0.5:1; The B component comprises the following raw materials in parts by weight: 40-50 parts of NCO-terminated polyurethane prepolymer, 10-20 parts of filler, and 30-40 parts of a second flame retardant; the NCO-terminated polyurethane prepolymer is prepared by reacting a second polyol with a diisocyanate; the -NCO content of the NCO-terminated polyurethane prepolymer is 8-12 wt%.
2. The two-component polyurethane photovoltaic sealing water-blocking adhesive according to claim 1, characterized in that, The mass ratio of the organosilicon compound, nano-silica, and polyvinyl alcohol is 3-5:0.1-0.3:
1.
3. The two-component polyurethane photovoltaic sealing water-blocking adhesive according to claim 1, characterized in that, The average particle size of the nano-silica is 15-60 nm; the organosilicon compound is selected from one or more combinations of methyl orthosilicate, ethyl orthosilicate, propyl orthosilicate, butyl orthosilicate, methyltrimethoxysilane, and methyltriethoxysilane; the weight-average molecular weight of the polyvinyl alcohol is 150,000-200,000.
4. The two-component polyurethane photovoltaic sealing water-blocking adhesive according to claim 1, characterized in that, The method for preparing the porous hybrid microspheres includes the following steps: preparing silica sol using organosilicon compounds as raw materials; mixing the silica sol with nano-silica and polyvinyl alcohol aqueous solution, reacting, freeze-drying, and air-jet milling to obtain porous hybrid microspheres.
5. The two-component polyurethane photovoltaic sealing water-blocking adhesive according to claim 4, characterized in that, The method for preparing the silica sol includes the following steps: mixing an organosilicon compound, an organic alcohol, and water, adjusting the pH to 2-4, and reacting at a controlled temperature to obtain the silica sol.
6. The two-component polyurethane photovoltaic sealing water-blocking adhesive according to claim 5, characterized in that, The mass ratio of the organosilicon compound, organic alcohol, and water is 1:1-5:0.1-0.
5. The temperature-controlled reaction is carried out at a temperature of 40-60℃ with stirring at 100-300 rpm for 1-2 hours.
7. The two-component polyurethane photovoltaic sealing water-blocking adhesive according to claim 1, characterized in that, The first polyol has a functionality of 2.5-3 and a hydroxyl value of 100-400 mg KOH / g; the first polyol is selected from one or more of modified castor oil polyol, modified palm oil polyol, modified cashew nut shell oil polyol, modified rapeseed oil polyol, and modified soybean oil polyol; preferably, the first polyol is a modified castor oil polyol with a functionality of 2.6-2.9 and a hydroxyl value of 109-342 mg KOH / g.
8. The two-component polyurethane photovoltaic sealing water-blocking adhesive according to claim 1, characterized in that, The second polyol has a functionality of 2-3 and a number-average molecular weight of 2000-6000; the second polyol is selected from one or more of hydrogenated hydroxyl-terminated polybutadiene, hydroxyl-terminated polybutadiene, polyethylene glycol, polypropylene glycol, and polypropylene triol; the diisocyanate is selected from one or more of isophorone diisocyanate, toluene diisocyanate, and diphenylmethane-4,4'-diisocyanate; preferably, the second polyol is hydrogenated hydroxyl-terminated polybutadiene and / or hydroxyl-terminated polybutadiene with a functionality of 2-2.3 and a number-average molecular weight of 3000-5000.
9. The two-component polyurethane photovoltaic sealing water-blocking adhesive according to claim 1, characterized in that, The preparation method of the NCO-terminated polyurethane prepolymer includes the following steps: adding a second polyol to a reaction vessel, dehydrating, cooling for the first time, adding diisocyanate and a second catalyst and mixing, reacting under controlled temperature under vacuum, and cooling for the second time to obtain the NCO-terminated polyurethane prepolymer.
10. A method for preparing the two-component polyurethane photovoltaic water-blocking adhesive according to any one of claims 1-9, characterized in that, Includes the following steps: 1) Mix the first polyol, porous hybrid microspheres, filler, first flame retardant, and second catalyst, and dehydrate to obtain component A; 2) Mix the filler and the second flame retardant, dehydrate, add NCO-terminated polyurethane prepolymer, mix, degas, and obtain component B.